STRSTR(3)                           Linux Programmer's Manual                           STRSTR(3)



NAME
       strstr, strcasestr - locate a substring

SYNOPSIS
       #include <string.h>

       char *strstr(const char *haystack, const char *needle);

       #define _GNU_SOURCE         /* See feature_test_macros(7) */

       #include <string.h>

       char *strcasestr(const char *haystack, const char *needle);

DESCRIPTION
       The  strstr()  function  finds  the first occurrence of the substring needle in the string
       haystack.  The terminating null bytes ('\0') are not compared.

       The strcasestr() function is like strstr(), but ignores the case of both arguments.

RETURN VALUE
       These functions return a pointer to the beginning of the located substring, or NULL if the
       substring is not found.

ATTRIBUTES
   Multithreading (see pthreads(7))
       The strstr() function is thread-safe.

       The strcasestr() function is thread-safe with exceptions.  It can be safely used in multi‐
       threaded applications, as long as setlocale(3) is not called to change the  locale  during
       its execution.

CONFORMING TO
       The strstr() function conforms to C89 and C99.  The strcasestr() function is a nonstandard
       extension.

SEE ALSO
       index(3),  memchr(3),  rindex(3),   strcasecmp(3),   strchr(3),   string(3),   strpbrk(3),
       strsep(3), strspn(3), strtok(3), wcsstr(3)

COLOPHON
       This  page  is  part of release 3.74 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.



GNU                                         2014-08-19                                  STRSTR(3)